1. Field of the Invention
This invention lies in the field of coupling links for joining sections of chain, and attaching fittings to chains and similar devices.
More particularly, it concerns a type of link which can be assembled easily in the field and can be disassembled with equal facility.
2. Description of the Prior Art
In the prior art, various types of coupling links with pins have been provided in which the pin is held by a number of different methods within the openings in the two halves of the link. One method is to hold the pin by means of a head on one end and a cotter pin, or other locking means, on the other end. In this type of construction, the pin extends beyond the outer surfaces of the coupling link, and provides certain difficulties in the use of the device, and is to be avoided.
Another type of coupling unit is illustrated by the reissue U.S. Pat. No. Re. 27,620, in which the pin is held in position in the coupled half links, by means of a spring sleeve. The unit is assembled by slipping the pin through a pair of ears and a meshed tongue, then through the spring sleeve, being driven into the sleeve by means of a hammer or a similar tool, and then through the other pair of ears.
While this type of spring sleeve provides adequate holding capacity for the pin, it does not hold the pin most effectively. Although the inner surface of the spring sleeve may be a cylindrical surface in its unstressed condition, when the pin is driven into the spring sleeve, the pin being larger in diameter than the inner diameter of the sleeve, the sleeve will be expanded to accommodate the entrance of the pin. Therefore, the cylindrical inner surface will be distorted and the sleeve will contact the pin along a few longitudinal lines along the surface. This will not provide a large area of frictional contact, which is desired to hold the pin in position. Furthermore, because of the fact that the spring does not contact a large area of the surface, the unit pressure along the few lines of contact will be so great that, in the process of inserting the pin into the sleeve and also in driving it out, the inner surface of the spring is scored, notched or gouged. Because the sleeve is under extreme stress these scored, notched or gouged areas become undesirable stress raisers or likely areas of failure.